1. Field of the Invention
The present invention is generally directed to radio frequency identification (RFID) technology.
2. Background Art RFID tags are electronic devices that may be affixed to items whose presence is to be detected and/or monitored. The presence of an RFID tag, and therefore the presence of the item to which the tag is affixed, may be checked and monitored by devices known as “readers.” Readers typically transmit radio frequency (RF) signals to which the RFID tags respond. Each RFID tag can store a unique identification number or other identifiable information. The RFID tags respond to the reader by backscatter transmitting their identification numbers or other identifiable information, so that the tags can be identified.
The environment in which an RFID tag is located may adversely affect a reader's ability to read the RFID tag. RFID tags may be affixed to a wide variety of products. These products may be located in many different kinds of environments. The different kinds of environments may have differing, and potentially adverse, effects on the RF signals transmitted and received by a reader. Specifically, the environment may be RF opaque, RF reflective, and/or RF absorptive. For example, an RFID tag affixed to a product that is located within a metallic container cannot be properly read from outside the metallic container because the metallic container is RF opaque. As another example, an RFID tag affixed to a product that is located face-down on a metallic shelf cannot be properly read because the product is RF opaque and the metallic shelf is RF reflective.
Given the foregoing, what is needed is an improved method and system for reading RFID tags.
The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.